Investments in Partially Owned Entities - Consolidated Variable Interest Entities ("VIEs") - Additional Information (Details) $ in Thousands	Jun. 30, 2021 USD ($) Property ApartmentUnit	Dec. 31, 2020 USD ($)
Variable Interest Entity [Line Items]
Properties | Property	303
Apartment units | ApartmentUnit	78,107
Total assets	$ 20,464,346	$ 20,286,891
Total liabilities	$ 9,382,176	9,184,454
Consolidated VIE [Member]
Variable Interest Entity [Line Items]
Properties | Property	16
Apartment units | ApartmentUnit	3,477
Total assets	$ 778,600	784,100
Total liabilities	$ 242,000	$ 224,000